1. Field of the Invention
The invention relates generally to hydrogen storage, production, and utilization for generating energy and more specifically to methods of producing hydrogen from re-usable hydrogen producing compounds and methods of regenerating spent compounds to a form suitable for hydrogen production, as well as devices and assemblies for producing hydrogen.
2. Background Information
A “hydrogen economy” is a an economy in which a substantial portion of energy generation occurs by use of hydrogen as a fuel. A hydrogen fuel based economy is particularly attractive and desirable due to the promise of a plentiful and environmentally clean energy source. Fuel cell technology, for example, continues to advance and offers the potential to convert hydrogen and oxygen (e.g., air) to energy, such as electricity, in an efficient manner, emitting only water. Changing to a more hydrogen fuel based system, however, requires a transition from the worldwide petrochemical production and delivery infrastructure and a conversion to a hydrogen fuel based system.
Sources for hydrogen storage and production are continuously being discovered and technologies advanced, and the cost of producing hydrogen fuel is continuously declining. Effective utilization of these technological advances and a transition to more hydrogen fuel based systems, however, is severely limited by the currently available sources of hydrogen storage and production. Current technologies are significantly lacking, for example, with regard to efficient and practical means for storage and delivery of hydrogen to locations where hydrogen consumption is desired.
Currently available methods of storing and delivering hydrogen fuel include, for example, compressed hydrogen, liquefied hydrogen, physical metal hydride storage, chemical hydride storage, nanotube storage, and others. Compressed and liquefied storage are primarily limited by the energy intensive, and therefore costly, methods needed to compress the hydrogen, as well as bulky and heavy tanks required to store the compressed/liquefied hydrogen, which can pose a severe explosive risk when positioned on-board a moving vehicle or automobile. Hydride storage is promising, but current methods are extremely expensive and far too heavy for practical use on-board a vehicle. It is estimated, for example, that a small metal hydride container holding less than 2 grams of hydrogen weighs 230 grams. Accordingly, storing the equivalent of 8 liters or 2 U.S. gallons of gasoline would require a hydride store weighing up to 200 kilograms or 440 pounds, making this type of hydrogen storage impractical, for example, for automobile applications (see, for example, Bossel et. al., April 2003 report: “The Future of the Hydrogen Economy: Bright or Bleak?”).
Unfortunately, devices and methods that are inexpensive, but efficient and lightweight, and practical for use on-board hydrogen powered vehicles, have not yet been discovered. Thus, a need exists for methods and devices for lightweight and efficient storage of hydrogen, which are useful for on-demand hydrogen production for energy generation on-board hydrogen powered vehicles.